Wireless Access Point, Terminal Device, and Method for Waking Up Terminal Device by Wireless Access Point

ABSTRACT

A wireless access point, a terminal device, and a method for waking up a terminal device by a wireless access point. The terminal device includes a primary radio frequency circuit and a wake-up radio (WUR) radio frequency circuit. The WUR radio frequency circuit only receives a radio signal and operates on a specified channel. If the WUR radio frequency circuit receives a wake-up frame on the specified channel and the terminal device is a to-be-woken-up terminal device, the WUR radio frequency circuit wakes up the primary radio frequency circuit. The wake-up frame includes an identifier of the to-be-woken-up terminal device. The primary radio frequency circuit operates on an operating channel of the primary radio frequency circuit after being woken up.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Patent ApplicationNo. PCT/CN2018/084581, filed on Apr. 26, 2018, which claims priority toChinese Patent Application No. 201710282884.8, filed on Apr. 26, 2017.The disclosures of the aforementioned applications are herebyincorporated by reference in their entireties.

TECHNICAL FIELD

This application relates to the communications field, and in particular,to a wireless access point, a terminal device, and a method for wakingup a terminal device by a wireless access point.

BACKGROUND

A terminal device in a wireless local area network (WLAN) may enter asleep mode. However, the terminal device in the sleep mode also needs tofrequently enter an awake state from a doze state to receive data.

SUMMARY

This application provides a wireless access point, a terminal device,and a method for waking up a terminal device, in order to reduce powerconsumption of a terminal device.

According to a first aspect, a terminal device is provided. The terminaldevice includes a primary radio frequency circuit and a wake-up radio(WUR) radio frequency circuit. The WUR radio frequency circuit isconfigured to only receive a radio signal and operate on a specifiedchannel. If the WUR radio frequency circuit receives a wake-up frame onthe specified channel and the terminal device is a to-be-woken-upterminal device, the WUR radio frequency circuit is further configuredto wake up the primary radio frequency circuit. The wake-up frameincludes an identifier of the to-be-woken-up terminal device. Theprimary radio frequency circuit is configured to operate on an operatingchannel of the primary radio frequency circuit after being woken up.

The WUR radio frequency circuit is a radio frequency circuit other thanthe primary radio frequency circuit in the terminal device. The WURradio frequency circuit can only receive a radio signal and cannot senda radio signal. The WUR radio frequency circuit is only configured toreceive a frame (e.g., a WUR frame) related to a wake-up operation, andignores other frames (for example, a WLAN data frame). Therefore, bothpower consumption and complexity of the WUR radio frequency circuit arerelatively low. Power consumption of the WUR radio frequency circuitthat is generated during operating may be less than 100 microwatts (μW).To wake up the terminal device in time, the WUR radio frequency circuitoperates on the specified channel. The WUR radio frequency circuit doesnot need to frequently switch a channel. Because another WLAN deviceknows the specified channel, the other WLAN device can send a wake-upframe on the specified channel. When operating on the specified channel,the WUR radio frequency circuit can receive the wake-up frame, to wakeup the primary radio frequency circuit.

With reference to the first aspect, in a first implementation of thefirst aspect, the primary radio frequency circuit is further configuredto receive information about the specified channel of the WUR radiofrequency circuit on the operating channel of the primary radiofrequency circuit. If the specified channel is dynamically negotiated,or the terminal device does not know the specified channel, a WLANdevice may notify the terminal device of the specified channel.

With reference to the first aspect or the first implementation of thefirst aspect, in a second implementation of the first aspect, anoperating band of the primary radio frequency circuit is the same as anoperating band of the WUR radio frequency circuit.

With reference to the first aspect, the first implementation of thefirst aspect, or the second implementation of the first aspect, in athird implementation of the first aspect, an operating channel availableto the primary radio frequency circuit is a WLAN channel other than thespecified channel. Because the operating channel and the specifiedchannel are different, inter-channel interference can be reduced.

With reference to any one of the first aspect, or the firstimplementation to the third implementation of the first aspect, in afourth implementation of the first aspect, the wake-up frame furtherincludes an indication for the operating channel, and the primary radiofrequency circuit is configured such that after being woken up, theprimary radio frequency circuit operates on the operating channelindicated by the wake-up frame. The wake-up frame indicates an operatingchannel of the WLAN device on which the wake-up frame is sent, such thatburden of the primary radio frequency circuit in scanning a channelafter the primary radio frequency circuit is woken up can be alleviated.

With reference to any one of the first aspect, or the firstimplementation to the fourth implementation of the first aspect, in afifth implementation of the first aspect, the identifier of theto-be-woken-up terminal device is an individual identifier of theterminal device, and the primary radio frequency circuit is furtherconfigured such that after being woken up, the primary radio frequencycircuit sends a response to the wake-up frame on the operating channelindicated by the wake-up frame. The terminal device responds to thewake-up frame, to notify the WLAN device that the terminal device hasbeen woken up. Because the WUR radio frequency circuit cannot send aradio signal, the primary radio frequency circuit of the terminal devicesends the response to the wake-up frame on the operating channel afterbeing woken up.

With reference to any one of the first aspect, or the firstimplementation to the fifth implementation of the first aspect, in asixth implementation of the first aspect, the WUR radio frequencycircuit is further configured to receive a WUR beacon frame, and if theWUR beacon frame indicates a new specified channel, operate on the newspecified channel. If a specified channel of the WLAN device is dynamic,the WLAN device may change the specified channel. To enable the terminaldevice to know a change of the specified channel, the WLAN devicenotifies the terminal device of the new specified channel.

According to a second aspect, a method for waking up a terminal deviceis provided. The method includes the steps performed by the terminaldevice in the first aspect.

According to a third aspect, a method for waking up a terminal device isprovided. The method includes: sending, by a WLAN device, a wake-upframe on a specified channel, where the wake-up frame includes anidentifier of a to-be-woken-up terminal device; and sending, by the WLANdevice, a WLAN frame on an operating channel.

With reference to the third aspect, in a first implementation of thethird aspect, the method further includes sending, by the WLAN device,information about the specified channel on the operating channel.

With reference to the third aspect or the first implementation of thethird aspect, in a second implementation of the third aspect, anoperating channel available to the WLAN device is a WLAN channel otherthan the specified channel.

With reference to the third aspect, the first implementation of thethird aspect, or the second implementation of the third aspect, in athird implementation of the third aspect, the wake-up frame furtherincludes an indication for the operating channel.

With reference to any one of the third aspect, or the firstimplementation to the third implementation of the third aspect, in afourth implementation of the third aspect, the identifier of theto-be-woken-up terminal device is an identifier of one terminal device,and the method further includes: if the WLAN device receives no responseto the wake-up frame on the operating channel, sending, by the WLANdevice, a new wake-up frame on the specified channel.

With reference to any one of the third aspect, or the firstimplementation to the fourth implementation of the third aspect, in afifth implementation of the third aspect, the identifier of theto-be-woken-up terminal device is a group identifier or a broadcastidentifier, the WLAN frame is a group addressed frame, and the WLANdevice sends the WLAN frame on the operating channel after a preparationperiod after the wake-up frame is sent. If the WLAN device sends thewake-up frame indicating that the identifier is a group identifier or abroadcast identifier, to wake up a plurality of terminal devices, theWLAN device does not need to determine whether each terminal device hasbeen woken up.

With reference to any one of the third aspect, or the firstimplementation to the fifth implementation of the third aspect, in asixth implementation of the third aspect, the method further includesperiodically sending, by the WLAN device, a wake-up radio (WUR) beaconframe on the specified channel, where the WUR beacon frame and a beaconframe on the operating channel are separately sent.

With reference to the sixth implementation of the third aspect, in aseventh implementation of the third aspect, the WUR beacon frameincludes an indication for the operating channel.

With reference to any one of the third aspect, or the firstimplementation to the seventh implementation of the third aspect, in aneighth implementation of the third aspect, the method further includes:before changing the specified channel, indicating, by the WLAN device, anew specified channel using the WUR beacon frame.

With reference to any one of the third aspect, or the firstimplementation to the eighth implementation of the third aspect, in aninth implementation of the third aspect, a WLAN band of the specifiedchannel is the same as a WLAN band of the operating channel.

According to a fourth aspect, an apparatus for waking up a terminaldevice is provided. The apparatus has functions of implementing thebehavior of the WLAN device in the method in the third aspect. Thefunctions may be implemented by hardware, or may be implemented byhardware by executing corresponding software. The hardware or thesoftware includes one or more modules corresponding to the foregoingfunctions.

According to a fifth aspect, a WLAN device is provided. The WLAN deviceincludes a processor and a transceiver. The processor is configured toreceive and send a radio signal using the transceiver, and perform thesteps in the method in the third aspect.

According to a sixth aspect, an embodiment of the present disclosureprovides a computer storage medium, configured to store a computersoftware instruction used by the foregoing WLAN device. The computersoftware instruction includes a program designed for executing theforegoing aspects.

According to a seventh aspect, an embodiment of the present disclosureprovides a computer storage medium, configured to store a computersoftware instruction used by the foregoing terminal device. The computersoftware instruction includes a program designed for executing theforegoing aspects.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram of a network architecture according to anembodiment of the present disclosure;

FIG. 2 is a schematic diagram of waking up a terminal device by a WLANdevice according to an embodiment of the present disclosure;

FIG. 3 is an example in which a terminal device moves in coverage areasof two WLAN devices according to an embodiment of the presentdisclosure;

FIG. 4 is another example in which a terminal device moves in coverageareas of two WLAN devices according to an embodiment of the presentdisclosure; and

FIG. 5 is a schematic diagram of an apparatus for waking up a terminaldevice according to an embodiment of the present disclosure.

DESCRIPTION OF EMBODIMENTS

The following describes the embodiments of the present disclosure withreference to FIG. 1 to FIG. 5.

In an internet of things scenario, many devices need to be powered bybatteries. Therefore, it is quite important to prolong lifespans (e.g.,battery lifespans) of the devices. Because a WLAN device is highlypopularized, if the WLAN device can be used to implement functionsrequired by the internet of things scenario, a threshold forpopularizing the internet of things can be reduced.

The WLAN device may enter a sleep mode. However, the WLAN device in thesleep mode also needs to frequently enter an awake state from a dozestate, to receive data of another WLAN device (for example, a wirelessaccess point (AP) or a WLAN device of another type). A longer time inwhich a device stays in the doze state contributes to less consumedenergy. However, staying in the doze state for a long time reducestimely performance of data transmission.

To reduce power consumption of the WLAN device as much as possible andmeet a requirement for timely performance of data transmission, adedicated wake-up radio (WUR) radio frequency circuit other than aprimary radio frequency (RF) circuit is disposed in the WLAN device inthe embodiments of the present disclosure. The WLAN device on which theWUR radio frequency circuit is disposed is referred to as a WUR terminaldevice or a terminal device. The WUR radio frequency circuit can onlyreceive a radio signal and cannot send a radio signal. The WUR radiofrequency circuit is only configured to receive a frame (which may bereferred to as a WUR frame such as a WUR beacon frame or a WUR wake-upframe) related to a wake-up operation, and ignores other frames (forexample, a data frame). Therefore, power consumption and complexity ofthe WUR radio frequency circuit are low. Power consumption of the WURradio frequency circuit that is generated during operating may be lessthan 100 microwatts (μW). The primary radio frequency circuit and theWUR radio frequency circuit may be separate, or may be integrated into achip.

When there is no data that is to be transmitted, the terminal device isin a sleep state. When the terminal device is in the sleep state, theprimary radio frequency circuit is disconnected for energy saving. Whenthe terminal device is in the sleep state, the WUR radio frequencycircuit listens to a wireless medium, to receive a wake-up frame intime. Optionally, the WUR radio frequency circuit may suspend operatingfor further energy saving. For example, the WUR radio frequency circuitmay periodically suspend operating. Further, when the terminal device isin the sleep state, any component except the WUR radio frequency circuitin the entire device may be in a power-off state. If the terminal deviceincludes a volatile memory, the volatile memory may not be in thepower-off state when the terminal device is in the sleep state.Alternatively, the terminal device may copy content in the volatilememory to a non-volatile memory before entering the sleep state, andthen disable the volatile memory when entering the sleep state.

When the WLAN device needs to send data to a terminal device, or needsto query data of a terminal device, the WLAN device first sends awake-up frame. After receiving the wake-up frame, a WUR radio frequencycircuit of a to-be-woken-up terminal device wakes up a primary radiofrequency circuit of the terminal device. In this case, the terminaldevice is in the awake state. After sending the wake-up frame, the WLANdevice sends a WLAN frame. The WLAN frame may be a data frame or amanagement frame. The data frame may include an indication for sendingthe data to the terminal device by the WLAN device or querying the dataof the terminal device.

In an example in which the WLAN device is a wireless AP, to reduceinterference between wireless APs, adjacent wireless APs usually operateon different operating channels. If wireless APs send WUR frames onrespective operating channels, adjacent wireless APs send WUR frames ondifferent channels.

After a terminal device moves from a coverage area of an originalwireless AP to a coverage area of an adjacent wireless AP, because theterminal device does not know an operating channel of the new wirelessAP, the terminal device can only switch to an operating channel of a WURradio frequency circuit, to attempt to listen to a WUR frame sent by thenew wireless AP. WLAN bands include a 900 megahertz (MHz) band, a 2.4gigahertz (GHz) band, a 3.65 GHz band, a 4.9 GHz band, a 5 GHz band, a5.9 GHz band, a 60 GHz band, and the like. Quantities of WLAN channelsincluded in different WLAN bands are specified by regulations of eachcountry/region. For example, there are 25 channels with a bandwidth of20 MHz in the 5 GHz band in the United States. Because the terminaldevice does not know the operating channel of the new wireless AP, theoperating channel of the WUR radio frequency circuit of the terminaldevice needs to be frequently switched, to find the operating channel ofthe new wireless AP from the 25 channels. Frequent channel switchingincreases power consumption of the WUR radio frequency circuit.

If a plurality of wireless APs in one area send WUR frames on a samechannel, when the terminal device randomly moves in the area, the WURradio frequency circuit of the terminal device may listen to the WURframe sent by the new wireless AP without a need to perform channelswitching.

FIG. 1 is a schematic diagram of a network architecture according to anembodiment of the present disclosure.

In FIG. 1, there are a plurality of wireless devices, namely, a WLANdevice 101 to a WLAN device 106.

In this embodiment of the present disclosure, although operatingchannels of the WLAN device 101 to the WLAN device 106 are different,the WLAN device 101 to the WLAN device 106 send WUR frames on a samespecified channel (e.g., a channel (CH) 165). When a terminal device 110randomly moves in coverage areas of the WLAN device 101 to the WLANdevice 106, a WUR radio frequency circuit of the terminal device 110 maylisten to a WUR frame sent by any wireless AP without a need to performchannel switching. Alternatively, after any WLAN device fails to send awake-up frame on an operating channel of the WLAN device, the WLANdevice sends the wake-up frame on the specified channel (the channel165). After the terminal device 110 leaves a coverage area of anoriginal WLAN device, the WUR radio frequency circuit of the terminaldevice 110 may listen to a WUR frame sent by any wireless AP, providedthat the WUR radio frequency circuit of the terminal device 110 isswitched to the specified channel.

FIG. 2 is a schematic diagram of waking up a terminal device by a WLANdevice according to an embodiment of the present disclosure.

An example in which a WLAN device 210 wakes up a terminal device 220 isused in FIG. 2, to describe a process in this embodiment of the presentdisclosure.

The WLAN device 210 includes a processor 212 and a transceiver 214. Theprocessor 212 may include a central processing unit (CPU), a networkprocessor (NP), a radio frequency circuit, an application-specificintegrated circuit (ASIC), a programmable logic device (PLD), or anycombination thereof. The PLD may be a complex programmable logic device(CPLD), a field programmable gate array (FPGA), generic array logic(GAL), or any combination thereof. The radio frequency circuit is alsoreferred to as an RF module, and is an electronic component for sendingand/or receiving a radio signal between devices. The circuits in theprocessor may be separate, or may be integrated into one or more chips.

The transceiver 214 may be an antenna. The antenna may include an arrayantenna, a multi-band antenna, a microstrip antenna, a directionalantenna, or any antenna of another type. The processor 212 receives andsends a radio signal using the transceiver 214.

Optionally, the WLAN device 210 further includes a memory. The memorymay be a separate device, or may be integrated into the processor 212.The memory may include a volatile memory such as a random access memory(RAM). The memory may alternatively include a non-volatile memory suchas a read-only memory (ROM), a flash memory, an optical disc, a magnetictape, a floppy disk, a hard disk, or a solid-state drive. The memory mayalternatively include any combination of the foregoing types ofmemories. If the processor 212 needs program code, the memory may storeprogram code and transmit the program code to the processor 212, suchthat the processor 212 implements this embodiment of the presentdisclosure according to an indication of the program code.

The terminal device 220 includes a primary radio frequency circuit 222and a WUR radio frequency circuit 224. There may be one or more primaryradio frequency circuits 222. There may be one or more WUR radiofrequency circuits 224. For example, an operating band of the primaryradio frequency circuit 222 is the same as an operating band of the WURradio frequency circuit 224. If the terminal device 220 includes aplurality of primary radio frequency circuits 222 with differentoperating bands, the terminal device 220 may include a plurality of WURradio frequency circuits 224 with corresponding operating bands. Foranother example, two or more primary radio frequency circuits 222 withdifferent operating bands may be woken up by one WUR radio frequencycircuit 224. The primary radio frequency circuit 222 and the WUR radiofrequency circuit 224 may share an antenna. The primary radio frequencycircuit 222 and the WUR radio frequency circuit 224 may alternativelyuse respective antennas. The following describes this embodiment of thepresent disclosure using a 5 GHz band as an example. This embodiment ofthe present disclosure may also be applied to another band.

The primary radio frequency circuit 222 is a radio frequency circuit ofthe terminal device 220 for receiving and sending WLAN data. Anoperating channel of the primary radio frequency circuit 222 may bereferred to as a primary connectivity radio channel.

The WUR radio frequency circuit 224 is a radio frequency circuit of theterminal device 220 for receiving a WUR frame. The WUR radio frequencycircuit 224 includes only a receiver and does not include a transmitter.Therefore, the WUR radio frequency circuit can only receive a radiosignal and cannot send a radio signal. An operating channel of the WURradio frequency circuit 224 may be referred to as a WUR channel. The WURradio frequency circuit 224 uses a specified channel as the WUR channel.Alternatively, the WUR channel includes a primary WUR channel and asecondary WUR channel. The primary WUR channel is the operating channelof the primary radio frequency circuit 222, and the secondary WURchannel is the specified channel. If the WLAN device 210 fails to send awake-up frame on the primary WUR channel, the WLAN device 210 switchesto the secondary WUR channel, to send the wake-up frame. If the terminaldevice 220 listens and obtains no WUR beacon frame on the primary WURchannel for a long time, the terminal device 220 switches to thesecondary WUR channel, to listen to a wireless medium. The specifiedchannel is a same channel on which a plurality of APs send WUR frames.

Optionally, the terminal device 220 may further include a processor. Theprocessor may include a CPU, an NP, an ASIC, a PLD, or any combinationthereof. Optionally, the terminal device 220 may further include amemory. The memory may include a volatile memory such as a random accessmemory (RAM). The memory may alternatively include a non-volatile memorysuch as a read-only memory (ROM), a flash memory, an optical disc, amagnetic tape, a floppy disk, a hard disk, or a solid-state drive. Thememory may alternatively include any combination of the foregoing typesof memories. The primary radio frequency circuit 222, the WUR radiofrequency circuit 224, the processor (if any), and the memory (if any)may be separate chips, or may be integrated into one or more chips.

A process of waking up the terminal device 220 by the WLAN device 210 isas follows.

231. The WLAN device 210 sends information about a specified channel onan operating channel of the WLAN device 210, and after receiving theinformation about the specified channel, a primary radio frequencycircuit of the terminal device 220 configures a specified channel of aWUR radio frequency circuit based on the information.

For example, the WLAN device 210 is the WLAN device 103 in FIG. 1, andthe terminal device 220 is the terminal device 110 in FIG. 1. Theoperating channel of the WLAN device 210 is a channel 44, and thespecified channel of the WLAN device 210 is a channel 165. The specifiedchannel of the WLAN device 210 may be fixed. For example, the specifiedchannel may be specified by a standard or a regulation, or may bespecified by a device vendor. The specified channel of the WLAN device210 may alternatively be statically configured. For example, thespecified channel may be manually configured as a specified value. Thespecified channel of the WLAN device 210 may alternatively bedynamically negotiated. For example, a plurality of WLAN devices 210 inan area negotiate a specified channel shared by the WLAN devices 210.

If the terminal device 220 knows the specified channel, step 231 may beomitted. Therefore, if the specified channel is fixed or staticallyconfigured, step 231 is optional. For example, if the specified channelspecified by the standard or the regulation is fixed for the terminaldevice 220, or specified channels are manually configured for both theWLAN device 210 and the terminal device 220, step 231 may be omitted.

If the specified channel is fixed or statically configured, a channel onwhich dynamic frequency selection (DFS) does not need to be performedmay be selected as the specified channel. For example, in the UnitedStates, Canada, Russia, Singapore, China, South Korea, Australia,Brazil, Taiwan, and New Zealand, one of a channel 149, a channel 153, achannel 157, a channel 161, and a channel 165 may be used as thespecified channel.

If the specified channel of the WLAN device 210 is dynamicallynegotiated, the WLAN device 210 may preferably select a channel on whichDFS does not need to be performed as the specified channel. For example,priorities of channels selected as specified channels may be configuredin the WLAN devices 210, and a priority of a channel on which DFS doesnot need to be performed is higher than a priority of another channel.

As specified in regulations of some countries/regions, DFS needs to beperformed on all channels in the 5 GHz band, or all channels in the 5GHz band can be only used indoors. If a WLAN is only used indoors, forexample, in an indoor internet of things scenario, the specified channelof the WLAN device 210 may be manually configured as an indoor channel.If a WLAN needs to be used outdoors, the WLAN device 210 performs DFSand then selects a valid WLAN channel as the specified channel.

If the specified channel of the WLAN device 210 is dynamicallynegotiated, or the specified channel is fixed or statically configured,but the terminal device 220 does not know the specified channel, theWLAN device 210 needs to notify the terminal device 220 of the specifiedchannel. The WLAN device 210 sends the information about the specifiedchannel on the operating channel. The information about the specifiedchannel may be carried in a WUR channel element. The WUR channel elementis a newly defined information element. A value of an element ID fieldof the WUR channel element is, for example, one of 143 to 173 or 175 to220. A length of an information field of the WUR channel element may bean octet, and the information field of the WUR channel element includesa channel number. For example, if the specified channel is the channel165, a value of the channel number of the WUR channel element is 165.The WUR channel element may be carried in one or more of a beacon frame,a probe response frame, and an action frame (for example, a spectrummanagement action frame or a WUR action frame).

The specified channel may be the same as or different from the operatingchannel of the WLAN device 210. For example, if the specified channel isthe channel 165, and operating channels of a plurality of WLAN devicesare respectively the channel 149, the channel 153, the channel 157, thechannel 161, and the channel 165, an operating channel of one of theWLAN devices is the same as the specified channel.

Optionally, to reduce interference between the operating channel and thespecified channel, an operating channel available to the WLAN device andthe primary radio frequency circuit may be configured as a WLAN channelother than the specified channel. For example, if the specified channelis the channel 165, the operating channel available to the WLAN deviceand the primary radio frequency circuit may be only a valid operatingchannel other than the channel 165.

If the specified channel is different from the operating channel of theWLAN device 210, the WLAN device 210 switches to the specified channelwhen being to send a WUR frame, and sends the WUR frame on the specifiedchannel. After sending the WUR frame, the WLAN device 210 returns to theoperating channel of the WLAN device 210.

232. The WLAN device 210 sends a WUR beacon frame on the specifiedchannel.

The WLAN device 210 periodically sends the WUR beacon frame on thespecified channel (for example, the channel 165). The WUR beacon frameis different from a beacon frame sent by the WLAN device 210 on theoperating channel (for example, the channel 44), and the WUR beaconframe and the beacon frame on the operating channel are separately sent.For example, a beacon interval of the WUR beacon frame may be fargreater than a beacon interval of the beacon frame. The beacon intervalof the WUR beacon frame may be carried in a WUR mode element. The WURmode element may be carried in one or more of a beacon frame, a proberesponse frame, and an action frame (for example, a WUR action frame) onthe operating channel.

If the WLAN device 210 sends the WUR beacon frame on the specifiedchannel, and the WUR radio frequency circuit 224 of the terminal device220 is enabled and operates on the specified channel, the terminaldevice 220 receives the WUR beacon frame. The terminal device 220 thatreceives the WUR beacon frame knows existence of the WLAN device 210that sends the WUR beacon frame. Optionally, the WUR beacon frame mayinclude an indication for the operating channel of the WLAN device 210.

The foregoing step 232 is optional, and the WLAN device 210 may not sendthe WUR beacon frame on the specified channel. For example, if theprimary WUR channel is the operating channel and the secondary WURchannel is the specified channel, the WLAN device 210 may only send theWUR beacon frame on the operating channel, and does not send the WURbeacon frame on the specified channel.

When the terminal device 220 is in a sleep state, the WUR radiofrequency circuit 224 of the terminal device 220 is enabled. Optionally,when the terminal device 220 is in an awake state, the terminal device220 may disconnect the WUR radio frequency circuit 224 for furtherenergy saving.

The WLAN device 210 may change the specified channel. For example, ifthe specified channel of the WLAN device 210 is dynamically negotiated,the WLAN device 210 may change the specified channel. Alternatively, ifthe specified channel of the WLAN device 210 is configured, thespecified channel may be changed in a new configuration. To enable theterminal device 220 to know a change of the specified channel, the WLANdevice 210 needs to notify the terminal device 220 of a new specifiedchannel. For example, before changing the specified channel, the WLANdevice 210 indicates a new specified channel using the WUR beacon frame.The WUR radio frequency circuit 224 receives the WUR beacon frame, andif the WUR beacon frame indicates a new specified channel, the WUR radiofrequency circuit 224 operates on the new specified channel. For anotherexample, if the secondary WUR channel is the specified channel, the WLANdevice 210 sends a change indication of the specified channel on thespecified channel, to indicate a new specified channel. The WUR radiofrequency circuit 224 that operates on the specified channel receivesthe change indication of the specified channel, and the WUR radiofrequency circuit 224 operates on the new specified channel according tothe indication. The change indication of the specified channel may be aWUR frame of a new type.

233. The WLAN device 210 sends a wake-up frame on the specified channel.

If the WLAN device 210 needs to wake up one or more terminal devices,the WLAN device 210 sends the wake-up frame on the specified channel.The wake-up frame in this embodiment of the present disclosure is a WURframe, and may also be referred to as a WUR wake-up frame. The wake-upframe includes an identifier of a to-be-woken-up terminal device. TheWUR radio frequency circuit 224 of the terminal device 220 receives thewake-up frame, and may determine, based on the identifier of theto-be-woken-up terminal device, whether the terminal device 220 is theto-be-woken-up terminal device. An identifier of the terminal device maybe an address of the terminal device, for example, a media accesscontrol (MAC) address, or may be an identifier of another type that canidentify the terminal device, for example, an association ID (AID) ofthe terminal device 220 and a combination of BSS colors of a basicservice set (BSS) associated with the terminal device 220. A BSS coloris an identifier for simplifying each BBS by the wireless AP in thearea. The identifier of the terminal device may be an identifier of oneterminal device, or may be a group identifier or a broadcast identifier.The group identifier indicates that all terminal devices in acorresponding group are to-be-woken-up terminal devices. The broadcastidentifier indicates that any terminal device is a to-be-woken-upterminal device.

If the WLAN device 210 needs to send a WLAN frame (for example, anindividually addressed frame) to one terminal device, the WLAN device210 sends the wake-up frame indicating that the identifier of theto-be-woken-up terminal device is an identifier of one terminal device,to wake up the terminal device.

If the WLAN device 210 needs to send a WLAN frame to a plurality ofterminal devices, the WLAN frame is a group addressed frame. The WLANdevice 210 sends the wake-up frame indicating that the identifier of theto-be-woken-up terminal device is a group identifier or a broadcastidentifier, to wake up the plurality of terminal devices. The WLANdevice 210 sends the group addressed frame on the operating channelafter a preparation period after the wake-up frame indicating that theidentifier is a group identifier or a broadcast identifier is sent.

The WLAN device 210 may modulate a payload of the WUR wake-up framethrough on-off keying (OOK). Correspondingly, the WUR radio frequencycircuit 224 demodulates the payload of the WUR wake-up frame throughOOK. The WUR wake-up frame may not occupy full bandwidth of thespecified channel, but only uses one or more orthogonal frequencydivision multiplexing (OFDM) subcarriers thereof.

If the WUR radio frequency circuit 224 receives the wake-up frame on thespecified channel and the terminal device 220 is the to-be-woken-upterminal device, the WUR radio frequency circuit 224 wakes up theprimary radio frequency circuit 222. For example, if the identifier ofthe to-be-woken-up terminal device is an identifier of one terminaldevice, and the identifier of the terminal device is the identifier ofthe terminal device 220, the WUR radio frequency circuit 224 wakes upthe primary radio frequency circuit 222. If the identifier of theto-be-woken-up terminal device is a group identifier, and the terminaldevice 220 is in a group identified by the group identifier, the WURradio frequency circuit 224 wakes up the primary radio frequency circuit222. If the identifier of the to-be-woken-up terminal device is abroadcast identifier, the WUR radio frequency circuit 224 wakes up theprimary radio frequency circuit 222.

The WUR radio frequency circuit 224 may directly wake up the primaryradio frequency circuit 222. Alternatively, the WUR radio frequencycircuit 224 may instruct the processor to wake up the primary radiofrequency circuit 222. After being woken up, the primary radio frequencycircuit operates on an operating channel available to the primary radiofrequency circuit.

Optionally, the wake-up frame may include the indication for theoperating channel of the WLAN device 210. The primary radio frequencycircuit 222 operates on the operating channel according to theindication after being woken up.

234. The primary radio frequency circuit 222 sends a response to thewake-up frame on the operating channel.

If the WLAN device 210 sends the wake-up frame indicating that theidentifier of the to-be-woken-up terminal device is the identifier ofone terminal device 220, to wake up the terminal device 220individually, the WLAN device 210 needs to determine whether theterminal device 220 has been woken up. Because the WUR radio frequencycircuit 224 cannot send a radio signal, the WUR radio frequency circuit224 cannot reply with an acknowledgement (ACK) frame on the specifiedchannel. Therefore, the primary radio frequency circuit 222 of theterminal device 220 sends the response to the wake-up frame on theoperating channel after being woken up. The response may be an ACKframe, a probe request frame, a data frame (for example, an empty dataframe), or any frame of another type, provided that the WLAN device 210knows that the terminal device 220 has been woken up. If the WLAN device210 receives the response to the wake-up frame on the operating channel,the WLAN device 210 knows that the terminal device 220 has beensuccessfully woken up. If the WLAN device 210 does not receive theresponse to the wake-up frame on the operating channel, it indicatesthat the WLAN device 210 fails to wake up the terminal device 220.

Optionally, if the WLAN device 210 does not receive the response to thewake-up frame on the operating channel, the WLAN device 210 notifiesanother WLAN device. The other WLAN device and the WLAN device 210 senda new wake-up frame on the specified channel. The new wake-up frameincludes the identifier of the terminal device 220. In addition, a newwake-up frame sent by each WLAN device includes an indication for anoperating channel of the corresponding WLAN device.

Optionally, if the WLAN device 210 does not receive the response to thewake-up frame on the operating channel, the WLAN device 210 sends a newwake-up frame on the specified channel. The new wake-up frame may be thesame as a previously sent wake-up frame. Alternatively, the new wake-upframe may be different from a previously sent wake-up frame. Forexample, if the operating channel of the WLAN device 210 changes whenthe WLAN device 210 waits for a response to the previously sent wake-upframe, an indication for the operating channel in the new wake-up framecorrespondingly changes.

Optionally, if the WLAN device 210 fails to wake up the terminal device220 for the first time, the WLAN device 210 attempts to wake up theterminal device 220 again. If the WLAN device 210 fails to wake up theterminal device 220 again after one or more attempts, the WLAN device210 instructs another WLAN device to send a wake-up frame.

If the WLAN device 210 sends the wake-up frame indicating that theidentifier of the to-be-woken-up terminal device is a group identifieror a broadcast identifier, step 234 may be omitted.

235. The WLAN device 210 sends a WLAN frame on the operating channel.

If the WLAN device 210 wakes up the terminal device 220 individually,the WLAN device 210 sends the WLAN frame to the terminal device 220 onthe operating channel after determining that the terminal device 220 hasbeen woken up. If the WLAN device 210 sends the wake-up frame indicatingthat the identifier is a group identifier or a broadcast identifier, towake up a plurality of terminal devices, the WLAN device 210 does notneed to determine whether each WLAN device 220 has been woken up. TheWLAN device 210 sends the WLAN frame such as a group addressed frame onthe operating channel after a preparation period after the wake-up frameis sent.

FIG. 3 is an example in which a terminal device moves in coverage areasof two WLAN devices according to an embodiment of the presentdisclosure. In FIG. 3, a terminal device 330 is associated with a WLANdevice 310 and then enters a sleep state. The terminal device 330 in thesleep state moves into a coverage area of a WLAN device 320 and then iswoken up by the WLAN device 320. For example, the WLAN device 310 is theWLAN device 103 in FIG. 1, the WLAN device 320 is the WLAN device 104 inFIG. 1, and the terminal device 330 is the terminal device 110 inFIG. 1. An operation process is as follows.

341. The WLAN device 310 sends information about a specified channel onan operating channel of the WLAN device 310, and after receiving theinformation about the specified channel, a primary radio frequencycircuit of the terminal device 330 configures a WUR channel of a WURradio frequency circuit as a specified channel based on the information.

The operating channel of the WLAN device 310 is a channel 44, and thespecified channel is a channel 165. The WLAN device 310 sendsinformation about the channel 165 on the channel 44. After receiving theinformation about the channel 165, the primary radio frequency circuitof the terminal device 330 configures the specified channel of the WURradio frequency circuit as the channel 165. Then, the terminal device330 enters the sleep state.

342. The WLAN device 310 sends a WUR beacon frame on the specifiedchannel, where the WUR beacon frame indicates a new specified channel.

The WLAN device 310 periodically sends the WUR beacon frame on thechannel 165. If the WLAN device 310 determines that the new specifiedchannel is a channel 161, the WUR beacon frame sent by the WLAN device310 on the channel 165 indicates that the channel 161 is the newspecified channel. The WUR radio frequency circuit of the terminaldevice 330 receives the WUR beacon frame, and configures the newspecified channel.

343. The WLAN device 310 sends the WUR beacon frame on the new specifiedchannel.

The WLAN device 310 periodically sends the WUR beacon frame on thechannel 161. The terminal device 330 in the sleep state can receive theWUR beacon frame when being in a coverage area of the WLAN device 310.If leaving the coverage area of the WLAN device 310, the terminal device330 in the sleep state cannot receive the WUR beacon frame.

344. The WLAN device 320 sends a WUR beacon frame on the new specifiedchannel.

The specified channel of the WLAN device 310 is the same as that of theWLAN device 320. When the WLAN device 310 changes the specified channelto the channel 161, the specified channel of the WLAN device 320 is alsochanged to the channel 161. After the specified channel is changed, theWLAN device 320 periodically sends the WUR beacon frame on the channel161. The terminal device 330 in the sleep state can receive the WURbeacon frame after entering the coverage area of the WLAN device 320.

345. The WLAN device 320 sends a wake-up frame on the new specifiedchannel.

When the WLAN device 320 needs to wake up the terminal device 330, theWLAN device 320 sends, on the channel 161, a wake-up frame that includesan identifier of the terminal device 330. The wake-up frame furtherincludes an indication for an operating channel (a channel 48) of theWLAN device 320. The WUR radio frequency circuit of the terminal device330 receives the wake-up frame.

346. The primary radio frequency circuit of the terminal device 330sends a response to the wake-up frame on an operating channel.

After receiving the wake-up frame, the WUR radio frequency circuit ofthe terminal device 330 wakes up the primary radio frequency circuit.Because the WUR radio frequency circuit cannot send a radio signal, theWUR radio frequency circuit cannot reply with an acknowledgement frameon the channel 161. Therefore, after being woken up, the primary radiofrequency circuit of the terminal device 330 sends the response to thewake-up frame on the channel 48.

If the WLAN device 320 does not receive the response to the wake-upframe on the channel 48, the WLAN device 320 sends a new wake-up frameon the channel 161. The new wake-up frame may be the same as apreviously sent wake-up frame. Alternatively, the new wake-up frame maybe different from a previously sent wake-up frame.

347. After determining that the terminal device 330 has been woken up,the WLAN device 320 sends a WLAN frame to the terminal device 330 on achannel 48.

FIG. 4 is another example in which a terminal device moves in coverageareas of two WLAN devices according to an embodiment of the presentdisclosure. In FIG. 4, a terminal device 430 is associated with a WLANdevice 410 and then enters a sleep state. The terminal device 430 in thesleep state moves into a coverage area of a WLAN device 420 and then iswoken up by the WLAN device 420. For example, the WLAN device 410 is theWLAN device 103 in FIG. 1, the WLAN device 420 is the WLAN device 104 inFIG. 1, and the terminal device 430 is the terminal device 110 inFIG. 1. An operation process is as follows.

441. The WLAN device 410 sends information about a specified channel onan operating channel of the WLAN device 410, and after receiving theinformation about the specified channel, a primary radio frequencycircuit of the terminal device 430 configures a specified channel of aWUR radio frequency circuit based on the information.

The operating channel of the WLAN device 410 is a channel 44, and thespecified channel is a channel 165. The WLAN device 410 sendsinformation about the channel 165 on the channel 44. After receiving theinformation about the channel 165, the primary radio frequency circuitof the terminal device 430 configures a secondary WUR channel of the WURradio frequency circuit as the specified channel (the channel 165).Then, the terminal device 430 enters the sleep state.

442. The WLAN device 410 sends a WUR beacon frame on the operatingchannel.

The WLAN device 410 periodically sends the WUR beacon frame on thechannel 44. If the WLAN device 410 determines a new specified channel,the WUR beacon frame sent by the WLAN device 410 on the channel 44indicates the new specified channel. The WUR radio frequency circuit ofthe terminal device 430 receives the WUR beacon frame, and configuresthe secondary WUR channel as the new specified channel.

443. The terminal device 430 in the sleep state leaves a coverage areaof the WLAN device 410, and cannot receive the WUR beacon frame sent bythe WLAN device 410 on the operating channel.

The terminal device 430 in the sleep state can receive the WUR beaconframe when being in the coverage area of the WLAN device 410. If leavingthe coverage area of the WLAN device 410, the terminal device 430 in thesleep state cannot receive the WUR beacon frame on the channel 44.

444. The WLAN device 420 sends a WUR beacon frame on an operatingchannel.

The operating channel of the WLAN device 420 is a channel 48. Theterminal device 430 in the sleep state cannot know an operating channelof a WLAN device falling in a coverage area of the terminal device 430.The WUR radio frequency circuit of the terminal device 430 in the sleepstate still operates on the channel 44, and therefore cannot receive theWUR beacon frame on the channel 48. If the terminal device 430 stillfails to listen and obtain the WUR beacon frame after one or more beaconintervals of the WUR beacon frame, the WUR radio frequency circuitoperates on the secondary WUR channel, namely, the channel 165.

445. The WLAN device 410 sends a wake-up frame on the operating channel.

When the WLAN device 410 needs to wake up the terminal device 430, theWLAN device 410 sends, on the channel 44, a wake-up frame that includesan identifier of the terminal device 430. Because the terminal device430 leaves the coverage area of the WLAN device 410, and the WUR radiofrequency circuit of the terminal device 430 operates on the secondaryWUR channel, namely, the channel 165, the terminal device 430 cannotreceive the wake-up frame from the WLAN device 410.

446. The WLAN device 410 instructs each WLAN device to send a wake-upframe on a specified channel.

Because the terminal device 430 is not woken up, and therefore does notrespond to the wake-up frame, the WLAN device 410 receives no responseto the wake-up frame on the channel 44. Optionally, the WLAN device 410may send a new wake-up frame on the channel 44. If the WLAN device 410fails to send the wake-up frame for the first time, or fails to resendthe wake-up frame, the WLAN device 410 instructs each WLAN device(including the WLAN device 420) to send, on the specified channel (thechannel 165), the wake-up frame that includes the identifier of theterminal device 430. In addition, each wake-up frame includes anindication for an operating channel of a corresponding WLAN device. TheWUR radio frequency circuit of the terminal device 430 operates on thesecondary WUR channel, namely, the channel 165. Therefore, the terminaldevice 430 receives the wake-up frame from the WLAN device 420. Thewake-up frame from the WLAN device 420 includes an indication for theoperating channel (the channel 48) of the WLAN device 420.

447. The primary radio frequency circuit of the terminal device 430sends a response to the wake-up frame on an operating channel (a channel48) indicated by the wake-up frame.

448. After determining that the terminal device 430 has been woken up,the WLAN device 420 sends a WLAN frame to the terminal device 430 on thechannel 48.

FIG. 5 is a schematic diagram of an apparatus for waking up a terminaldevice according to an embodiment of the present disclosure. Theapparatus for waking up a terminal device is implemented by any WLANdevice in FIG. 1. The apparatus for waking up a terminal device includesa wake-up module 502 and a sending module 504. The wake-up module isconfigured to send a wake-up frame on a specified channel, and thewake-up frame includes an identifier of a to-be-woken-up terminaldevice. The sending module is configured to send a WLAN frame on anoperating channel. For details about the apparatus for waking up aterminal device, refer to the content of the foregoing embodiments shownin FIG. 1 to FIG. 4.

All or some of the foregoing embodiments may be implemented usingsoftware, hardware, or a combination thereof. When the software or thecombination of software and hardware is used to implement theembodiments, all or some of the embodiments may be implemented in a formof a computer program product. The computer program product includes oneor more computer instructions. When the computer program instructionsare loaded and executed on a computer, the procedures or functionsaccording to the embodiments of the present disclosure are all orpartially generated. The computer may be a general-purpose computer, adedicated computer, a computer network, or another programmableapparatus. The computer instructions may be stored in a storage mediumor may be transmitted from one storage medium to another storage medium.For example, the computer instructions may be transmitted from onewebsite, computer, server, or data center to another website, computer,server, or data center in a wired (for example, a coaxial cable, atwisted pair, or an optical fiber) or wireless (for example, infrared,radio, or microwave) manner. The storage medium may be any usable mediumaccessible by a computer, or a data storage device, such as a server ora data center, integrating one or more media. The usable medium may be amagnetic medium (for example, a floppy disk, a hard disk, or a magnetictape), an optical medium (for example, an optical disc), a semiconductormedium (for example, a solid-state drive (SSD)), or the like.

The foregoing descriptions are merely example embodiments of the presentdisclosure, but are not intended to limit the protection scope of thepresent disclosure. Any variation or replacement readily figured out bya person skilled in the art within the technical scope disclosed in thepresent disclosure shall fall within the protection scope of the presentdisclosure. Therefore, the protection scope of the present disclosureshall be subject to the protection scope of the claims.

What is claimed is:
 1. A terminal device, comprising: a primary radiofrequency circuit configured to operate on an operating channel of theprimary radio frequency circuit after being woken up; and a wake-upradio (WUR) radio frequency circuit configured to: receive only a radiosignal; operate on one specified channel; and wake up the primary radiofrequency circuit when receiving a wake-up frame on the specifiedchannel and when the terminal device is a to-be-woken-up terminaldevice, wherein the wake-up frame comprises an identifier of theto-be-woken-up terminal device.
 2. The terminal device according toclaim 1, wherein the primary radio frequency circuit is furtherconfigured to receive information about the specified channel of the WURradio frequency circuit on the operating channel.
 3. The terminal deviceaccording to claim 1, wherein an operating channel available to theprimary radio frequency circuit is a wireless local area network (WLAN)channel other than the specified channel.
 4. The terminal deviceaccording to claim 1, wherein the wake-up frame further comprises anindication for the operating channel, and wherein the primary radiofrequency circuit is further configured to operate on the operatingchannel indicated by the wake-up frame after being woken up.
 5. Theterminal device according to claim 1, wherein the WUR radio frequencycircuit is further configured to: receive a WUR beacon frame indicatinga new specified channel; and operate on the new specified channel. 6.The terminal device according to claim 1, wherein an operating band ofthe primary radio frequency circuit is the same as an operating band ofthe WUR radio frequency circuit.
 7. A method for waking up a terminaldevice, the method comprising: receiving, by a wake-up radio (WUR) radiofrequency circuit of the terminal device, only a radio signal; operatingon one specified channel; waking up, by the WUR radio frequency circuit,a primary radio frequency circuit of the terminal device if the WURradio frequency circuit receives a wake-up frame and the terminal deviceis a to-be-woken-up terminal device, wherein the wake-up frame comprisesan identifier of the to-be-woken-up terminal device; and operating, bythe primary radio frequency circuit, on an operating channel of theprimary radio frequency circuit after being woken up.
 8. The methodaccording to claim 7, wherein the method further comprises receiving, bythe primary radio frequency circuit, information about the specifiedchannel of the WUR radio frequency circuit on the operating channel ofthe primary radio frequency circuit.
 9. The method according to claim 7,wherein an operating channel available to the primary radio frequencycircuit is a wireless local area network (WLAN) channel other than thespecified channel.
 10. The method according to claim 7, wherein thewake-up frame further comprises an indication for the operating channel,and wherein the method further comprises operating, by the primary radiofrequency circuit after being woken up, on the operating channelindicated by the wake-up frame.
 11. The method according to claim 7,wherein the method further comprises: receiving, by the WUR radiofrequency circuit, a WUR beacon frame; and operating, by the WUR radiofrequency circuit if the WUR beacon frame indicates a new specifiedchannel, on the new specified channel.
 12. The method according to claim7, wherein an operating band of the primary radio frequency circuit isthe same as an operating band of the WUR radio frequency circuit.
 13. Amethod for waking up a terminal device implemented by a wireless localarea network (WLAN) device, the method comprising: sending a wake-upframe on one specified channel, wherein the wake-up frame comprises anidentifier of a terminal device that is to be woken up; and sending aWLAN frame on an operating channel.
 14. The method according to claim13, further comprising sending information about the specified channelon the operating channel.
 15. The method according to claim 13, whereinthe operating channel is a WLAN channel other than the specifiedchannel.
 16. The method according to claim 13, wherein the wake-up framefurther comprises an indication for the operating channel.
 17. Themethod according to claim 13, wherein the identifier is a groupidentifier or a broadcast identifier, wherein the WLAN frame is a groupaddressed frame, and wherein the method further comprises: waiting for apreparation period after sending the wake-up frame; and sending the WLANframe after waiting for the preparation period.
 18. The method accordingto claim 13, wherein the method further comprises periodically sending awake-up radio (WUR) beacon frame on the specified channel, wherein theWUR beacon frame and a beacon frame on the operating channel areseparately sent.
 19. The method according to claim 18, wherein themethod further comprises indicating a new specified channel using theWUR beacon frame; and changing the specified channel to the newspecified channel.
 20. A wireless local area network (WLAN) device,comprising: a transceiver; and a processor coupled to the transceiverand configured to: send, via the transceiver, a wake-up frame on aspecified channel, wherein the wake-up frame comprises an identifier ofa to-be-woken-up terminal device; and send, via the transceiver, a WLANframe on an operating channel.
 21. The WLAN device according to claim20, wherein the processor is further configured to send informationabout the specified channel on the operating channel.
 22. The WLANdevice according to claim 20, wherein an operating channel available tothe WLAN device is a wireless local area network WLAN channel other thanthe specified channel.
 23. The WLAN device according to claim 20,wherein the wake-up frame further comprises an indication for theoperating channel.
 24. The WLAN device according to claim 20, whereinthe identifier of the to-be-woken-up terminal device is a groupidentifier or a broadcast identifier, wherein the WLAN frame is a groupaddressed frame, and wherein the processor is configured to send theWLAN frame on the operating channel after a preparation period after thewake-up frame is sent.
 25. The WLAN device according to claim 20,wherein the processor is further configured to periodically send awake-up radio (WUR) beacon frame on the specified channel, wherein theWUR beacon frame and a beacon frame on the operating channel areseparately sent.
 26. The WLAN device according to claim 25, wherein theprocessor is further configured such that before the specified channelis changed, the processor indicates a new specified channel using theWUR beacon frame.